content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import java.util.concurrent.Callable;
  
  import io.reactivex.common.*;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.functions.Action;
  import io.reactivex.observable.*;
  
  /**
   * Executes an Action and signals its exception or completes normally.
   *
   * @param <T> the value type
   */
  public final class MaybeFromAction<T> extends Maybe<T> implements Callable<T> {
  
      final Action action;
  
      public MaybeFromAction(Action action) {
          this.action = action;
      }
  
      @Override
      protected void subscribeActual(MaybeObserver<? super T> observer) {
          Disposable d = Disposables.empty();
          observer.onSubscribe(d);
  
          if (!d.isDisposed()) {
  
              try {
                  action.run();
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  if (!d.isDisposed()) {
                      observer.onError(ex);
                  } else {
                      RxJavaCommonPlugins.onError(ex);
                  }
                  return;
              }
  
              if (!d.isDisposed()) {
                  observer.onComplete();
              }
          }
      }
  
      @Override
      public T call() throws Exception {
          action.run();
          return null; // considered as onComplete()
      }
  }
  